Apparatus for drawing glass sheet



Feb. 1, 1966 W. J. BURKE 3,232,734

APPARATUS FOR DRAWING GLASS SHEET Filed Nov. 8, 1961 F'IG.1 F a INVENTOR. #441751? J 6024! United States Patent 3,232,734 APPARATUS FOR DRAWING GLASS SHEET Walter J. Burke, Brackenridge, Pa., assignor to Pittsburgh Plate Glass Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 8, 1961, Ser. No. 150,944 4 Claims. ((21. 65203) The application relates to the manufacture of sheet glass and, more particularly, to an improved gas burner for use in a sheet glass drawing chamber.

In the manufacture of sheet glass, gas burners are employed in the drawing chamber for influencing air currents which occur therein and which affect the appearance or, as referred 'to in the art, the pattern of the glass. Examples of the use of burners within sheet glass d-r-awing chambers are found in United States Letters Patent to Brich'ard, No. 2,693,052, issued November 2, 1954, entitled, Process of and Apparatus for Drawing Glass, and the copending application for United States Letters Patent of Robert A. James and Cecil R. Ward, Serial No. 771,393, filed November 3, 1958, now Patent No. 3,097,942 entitled Manufacture of Glass. The main purpose of such burners is to provide strong convection currents of gases, so as to influence the normally occurring air currents within the drawing chamber. To do so, a high velocity mixture of air and combustible gas is fed to the burners. However, because of the high velocity of the gas mixture as fed to the burners, the flames thereof have a tendency to blow-ofl, that is, lose their flames. The loss of flames, of course, affects the stability of the drawing operation. Not only is the drawing operation upset but the uniformity of the product is seriously affected. In addition to the above enumerated drawbacks, the usual burners emit radiant energy to the drawing chamber already at a relatively high temperature which results in a slow-down of the sheet cooling process. The slow-down in the cooling of the sheet results in a decrease in the rate of sheet production so that the product costs more to manufacture.

The invention to be described herein eliminates the difficulties and undesirable results enumerated vabove and encountered with the usual burners illustrated in the patent and in the patent application previously identified. The burner is so constructed with means to absorb its emitted radiant energy.

Thus, a new and novel burner structure will be described. The burner includes a flame retainer to eliminate flame blow-01f and is constructed with water cooling means to absorb its emitted radiant energy. In addition, the burner is constructed to restrict the width of the flame or the hot gases of combustion and provide a directional characteristic to the discharge blast. An increased velocity stream of gases is thus emitted from the burner structure which improves the convection current control in the drawing chamber. The net result is a material enhancement in the production of improved quality of sheet glass.

The burner to be described is also constructed to include a combustion chamber to insure near complete combustion of the combustible gas mixture. The burner is thus more efficient than the conventional burners previously used in sheet glass drawing processes which were merely circular pipes with nozzle openings therethrough.

The burner to be described in this application is an improvement over the burners described and illustrated in the applications for United States Letters Patents Numbers 118,080 and 118,079, filed June 19, 1961, by Norman Shorr and Richard P. Parobeck, both entitled, Manufacture of Glass.

The burner of this invention comprises a tubular member, generally rectangular in section, of a predetermined 3,232,734 t t Feb: 36

length having a plurality of nozzle openings through its wall, the nozzle openings being'prefer'ably arranged in a pattern having both length and width dimensions and along one side of the rectangle. Overlying the nozzle openings is a metal rod of a heat resisting material, such as nickel or ceramic which acts as a flame retainer for the burner. The metal rod is generally of the same length as the tubular member and is supported above and spaced from the nozzle openings. The metal rod fl me retainer is'supported along its length by upstanding brackets attached to the tubularmember. A' pair of angle members of generally the'same length as the tubular member overlie the metal rod flame retainer and the nozzle openings. Each angle has one leg connected to the tubular member and the other leg spaced fromithe tubular member. The angle members are spaced apart to define a combustion chamber'in which is located the flame retainer. A slot is thus formed by the'spaced angle members through which flames or hot combustion gases pass. Directionality is impartedto the flames or combustion gases by the slot;

'Water is passed through a cooling tube supported centrally of the tubular member and the tube ends are connected to a suitable source of cooling water.

To further understand the inventivefeatures broadly described above, attention is now directed to the drawing accompanying this specification which forms "a part of the specification and in which like reference characters are used to refer to like parts. In the drawing,

FIG. 1 is a schematicof a sheet bl-ass drawing kiln illustrating a drawing chamber and a burner therein in accordance with this invention; and

FIG. 2 is an isometric view of a burner constructed in accordance with the teachings of this invention and adapted for use in accordance with FIG. 1.

Referring now to the drawing, there is illustrated a burner B in which 10 is an elongated tubular member for connection to a source of combustible, preferably a mixture of gas and air. A plurality of nozzles or openings 12 are drilled into one surface of the tubular member and the combustible passes from the tubular member 10 through the nozzles into a combustion chamber 14. The combustion chamber is defined by a pair of spaced angle members 16 having leg portions which are connected to the tubular member 10 by means of spaced brackets 18 cooperating with elongated bars 20 connected to the member 10 as shown. Spacer members 21 welded to the angle members 16 maintain the proper spacing therebetween. The spaced angle members 16 define an elongated slot 22 through which flames or hot gases of combustion pass from the combustion chamber 14. The elongated slot 22 gives directionality to the flames or the hot gases of combustion. A metal rod 24 having a length substantially equal to that of the tubular member 10 runs centrally of the combustion chamber 14 and is supported by upstanding lugs 26 substantially equally spaced along the tubular member 10 and welded thereto. A pipe 28 runs cent-rally through the tubular member 10 and is connected to a suitable source of cooling fluid, such as water. The tube 28 thus serves to absorb emitted radiant energy from the burner structure described. The metal rod 24 serves as a flame retainer and during operation becomes heated to incandescence. This insures a complete burning of the combustible mixture within the chamber 14, so that the flame will not blow-off due to the high entrance velocity thereof.

Turning specifically to FIG. 1, we see the burner in its location for use in a drawing chamber of a sheet glass drawing apparatus. A sheet of glass is drawn from a bath of molten glass 102 through a cooled drawing chamber 104 by means of pairs of rolls 106 of a drawing machine 138. A refractory shape 110 known as a draw I stability of that process.

bar is submerged within the bath 192 and defines the 102, ventilator coolers 114, catch pan coolers 116 at the base of the drawing machine 108, and end walls 118. Machine coolers 120 are located on opposite sides of the sheet and extend the width of 'the sheet. The burners B are located on the lips of the L-blocks with their flames and/or products of combustion being discharged generally upwardly" and perhaps towards the sheet 100.

The burners B influence the air currents as in the aforementioned James and Ward application and increase the Other embodiments of the inverition will be apparent Without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A- gas burner comprising an elongated tubular memher for connection to a supply of gaseous fuel and having nozzle openings, and means overlying said flame retaining means to restrict the width of flames and products :of combustion from said burner and define a combustion chamber with the tubular member, said flame retaining means comprising a heat resistant rod extending a the length of the burner.

2. A burner as recited in claim l whe-rein said restricting means comprises a pair of angle members each having one leg attached to said tubular member and the other legdefining a restricted opening therebetween, further ineluding bracket members upstanding -from said tubular member to support said flame retaining means and also partially support said restricting means.

3. A burner as recited in claim 2 and further including means for absorbing radiant energy from said burner, said means including a pipe member passing through said tubular member and being connected to a source of cooling fluid. V

4. Apparatus for drawing sheet glass from a bath of molten glass comprising a cooled drawing chamber, and at least one burner for influencing air currents in the drawing chamber, said burner including a tubular member extending substantially the width of the drawing chamber for connection to a source of combustible gas, a plurality of nozzle openings through said tubular member, a flame retainer for said burner comprising an elongated rod spaced above said nozzle openings and extending the length of said tubular, member, means to restrict the width of flames and products of combustion from said burner while defining a combustion chamber in which is located said flame retainer, and means to absorb radiant energy emitted by said burner.

References Cited by the Examiner UNITED STATES PATENTS v 2,543,688 2/ 1951 Coriolis et a1. 2,632,503 3/ 1953 Bailey. 2,693,052 11/1954 Brichard 204 X 2,834,408 5/1958 Reinhart et al. 1581 15 2,963,820 12/ 1960 'Brichard 65-203 3,037,553 6/ 1962 Jackson.

DONALL H. SYLVESTER, Primary Examiner. 

1. A GAS BURNER COMPRISING AN ELONGATED TUBULAR MEMBER FOR CONNECTION TO A SUPPLY OF GASEOUS FUEL AND HAVING A PLURALITY OF NOZZLE OPENINGS THERETHROUGH FOR THE PASSAGE OF SAID FUEL, SAID OPENINGS BEING ARRANGED IN A PREDETERMINED ORDERLY PATTERN, MENAS OVERLYING SAID NOZZLE OPENINGS TO RETAIN A FLAME AT THE OUTER EXTREMITY OF THE NOZZLE OPENINGS, AND MEANS OVERLYING SAID FLAME RETAINING MEANS TO RESTRICT THE WIDTH OF FLAMES AND PRODUCTS OF COMBUSTION FROM SAID BURNER AND DEFINE A COMBUSTION CHAMBER WITH THE TUBULAR MEMBER, SAID FLAME RETAINING MEANS COMPRISING A HEAT RESISTANT ROD EXTENDING THE LENGTH OF THE BURNER.
 4. APPARATUS FOR DRAWING SHEET GLASS FROM A BATH OF MOLTEN GLASS COMPRISING A COOLED DRAWING CHAMBER, AND AT LEAST ONE BURNER FOR INFLUENCING AIR CURRENTS IN THE DRAWING CHAMBER, SAID BURNER INCLUDING A TUBULAR MEMBER EXTENDING SUBSTANTIALLY THE WIDTH OF THE DRAWING CHAMBER FOR CONNECTION TO A SOURCE OF COMBUSTIBLE GAS, A PLURALITY OF NOZZLE OPENINGS THROUGH SAID TUBULAR MEMBER, A FLAME RETAINER FOR SAID BURNER COMPRISING AN ELONGATED ROD SPACED ABOVE SAID NOZZLE OPENINGS AND EXTENDING THE LENGTH OF SAID TUBULAR MEMBER, MEANS TO RESTRICT THE WIDTH OF FLAMES AND PRODUCTS OF COMBUSTION FROM SAID BURNER WHILE DEFINING A COMBUSTION CHAMBER IN WHICH IS LOCATED SAID FLAME RETAINER, AND MEANS TO ABSORB RADIANT ENERGY EMITTED BY SAID BURNER. 